A vanguard of insurers is adapting its business model to the realities of climate change. In many ways, insurers are still catching up both to mainstream science and to their customers, which, in response to climate change and energy volatility, are increasingly changing the way they construct buildings, transport people and goods, design products and produce energy. Customers, as well as regulators and shareholders, are eager to see insurers provide more products and services that respond to the ?greening? of the global economy, expand their efforts to improve disaster resilience and otherwise be proactive about the climate change threat. Insurers are increasingly recognising the issue as one of ?enterprise risk management? (ERM), one cutting across the domains of underwriting, asset management and corporate governance. Their responses are becoming correspondingly sophisticated. Based on a review of more than 300 source documents, plus a direct survey of insurance companies, we have identified 643 specific activities from 244 insurance entities from 29 countries, representing a 50 per cent year-over-year increase in activity. These entities collectively represent $1.2 trillion in annual premiums and $13 trillion in assets, while employing 2.2 million people. In addition to activities on the part of 189 insurers, eight reinsurers, 20 intermediaries and 27 insurance organisations, we identified 34 non-insurance entities that have collaborated in these efforts. Challenges and opportunities include bringing promising products and services to scale, continuing to identify and fill market and coverage gaps and identifying and confirming the veracity of green improvements. There is also need for convergence between sustainability and disaster resilience, greater engagement by insurers in adaptation to unavoidable climate changes and to clarify the role that regulators will play in moving the market. It has not yet been demonstrated how some insurance lines might respond to climate change and a number of market segments have not yet been served with a single green insurance product or service. As insurer activities obtain more prominence, they also will be subject to more scrutiny and expectations that they are not simply greenwashing.